Actor–network theory, often abbreviated as ANT, is an approach to social theory and research, originating in the field of science studies, which treats objects as part of social networks. Although it is best known for its controversial insistence on the capacity of nonhumans to act or participate in systems and/or networks, ANT is also associated with forceful critiques of conventional and critical sociology. Developed by science and technology studies scholars Michel Callon and Bruno Latour, the sociologist John Law, and others, it can more technically be described as a "material-semiotic" method. This means that it maps relations that are simultaneously material (between things) and semiotic (between concepts). It assumes that many relations are both material and semiotic.

Broadly speaking, ANT is a constructivist approach in that it avoids essentialist explanations of events or innovations (e.g. explaining a successful theory by saying it is “true” and the others are “false”). However, it is distinguished from many other STS and sociological network theories for its distinct material-semiotic approach.

ANT appears to reflect many of the preoccupations of French post-structuralism, and in particular a concern with non-foundational and multiple material-semiotic relations. At the same time, it was much more firmly embedded in English-language academic traditions than most post-structuralist-influenced approaches. Its grounding in (predominantly English) science and technology studies was reflected in an intense commitment to the development of theory through qualitative empirical case-studies. Its links with largely US-originated work on large technical systems were reflected in its willingness to analyse large scale technological developments in an even-handed manner to include political, organizational, legal, technical and scientific factors.

Many of the characteristic ANT tools (including the notions of translation, generalized symmetry and the “heterogeneous network”), together with a scientometric tool for mapping innovations in science and technology (“co-word analysis”) were initially developed during the 1980s, predominantly in and around the CSI. The “state of the art” of ANT in the late 1980s is well-described in Latour’s 1987 text, Science in Action[1]

From about 1990 onwards, ANT started to become popular as a tool for analysis in a range of fields beyond STS. It was picked up and developed by authors in parts of organizational analysis, informatics, health studies, geography, sociology, anthropology, feminist studies and economics.

As of 2008, ANT is a widespread, if controversial range of material-semiotic approaches for the analysis of heterogeneous relations. In part because of its popularity, it is interpreted and used in a wide range of alternative and sometimes incompatible ways. There is no orthodoxy in current ANT, and different authors use the approach in substantially different ways. Some authors talk of “after-ANT” to refer to “successor projects” blending together different problem-focuses with those of ANT.[2]

Although it is called a “theory”, ANT does not usually explain “why” or "how" a network takes the form that it does.[3] Rather, ANT is a way of thoroughly exploring the relational ties within a network (which can be a multitude of different things). As Latour notes,[4] "explanation does not follow from description; it is description taken that much further." It is not, in other words, a theory "of" anything, but rather a method, or a "how-to book" as Latour [3] puts it.

The most central concept in ANT is the actor-network.The term "network" is somewhat problematic in that it, as Latour [3][4][7] notes, has a number of unwanted connotations. Firstly, it implies that what is described takes the shape of a network, which is not necessarily the case. Secondly, it implies "transportation without deformation," which, in ANT, is not possible since any actor-network involves a vast number of translations. Latour,[7] however, still contends that network is a fitting term to use, because "it has no a priori order relation; it is not tied to the axiological myth of a top and of a bottom of society; it makes absolutely no assumption whether a specific locus is macro- or micro- and does not modify the tools to study the element 'a' or the element 'b'." This use of the term "network" is very similar to Deleuze and Guattari's rhizomes; Latour [4] even remarks tongue in cheek that he would have no objection to renaming ANT "actant-rhizome ontology" if it only had sounded better, which hints at Latour's uneasiness with the word "theory".

Actor–network theory tries to explain how material–semiotic networks come together to act as a whole; the clusters of actors involved in creating meaning are both material and semiotic. As a part of this it may look at explicit strategies for relating different elements together into a network so that they form an apparently coherent whole. These networks are potentially transient, existing in a constant making and re-making.[3] This means that relations need to be repeatedly “performed” or the network will dissolve. They also assume that networks of relations are not intrinsically coherent, and may indeed contain conflicts. Social relations, in other words, are only ever in process, and must be performed continuously.

Actants denote human and non-human actors, and in a network take the shape that they do by virtue of their relations with one another. It assumes that nothing lies outside the network of relations, and as noted above, suggests that there is no difference in the ability of technology, humans, animals, or other non-humans to act (and that there are only enacted alliances.) As soon as an actor engages with an actor-network it too is caught up in the web of relations, and becomes part of the “Entelechy”.

If taken to its logical conclusion, then, nearly any actor can be considered merely a sum of other, smaller actors. A car is an example of a complex system. It contains many electronic and mechanical components, all of which are essentially hidden from view to the driver, who simply deals with the car as a single object. This effect is known as punctualisation, and is similar to the idea of abstraction in object-oriented programming.

When an actor network breaks down, the punctualisation effect tends to cease as well. In the automobile example above, a non-working engine would cause the driver to become aware of the car as a collection of parts rather than just a vehicle capable of transporting him or her from place to place. This can also occur when elements of a network act contrarily to the network as a whole. In his book Pandora’s Hope, Latour likens depunctualization to the opening of a black box. When closed, the box is perceived simply as a box, although when it is opened all elements inside it becomes visible.

ANT is often associated with the equal treatment of human and non-human actors. ANT assumes that all entities in a network can and should be described in the same terms. This is called the principle of generalized symmetry. The rationale for this is that differences between them are generated in the network of relations, and should not be presupposed.

The distinction between intermediaries and mediators is key to ANT sociology. Intermediaries are entities which make no difference (to some interesting state of affairs which we are studying) and so can be ignored. They transport the force of some other entity more or less without transformation and so are fairly uninteresting. Mediators are entities which multiply difference and so should be the object of study. Their outputs cannot be predicted by their inputs. From an ANT point of view sociology has tended to treat too much of the world as intermediaries.

For instance, a sociologist might take silk and nylon as intermediaries, holding that the former “means”, “reflects”, or “symbolises” the upper classes and the latter the lower classes. In such a view the real world silk–nylon difference is irrelevant — presumably many other material differences could also, and do also, transport this class distinction. But taken as mediators these fabrics would have to be engaged with by the analyst in their specificity: the internal real-world complexities of silk and nylon suddenly appear relevant, and are seen as actively constructing the ideological class distinction which they once merely reflected.

For the committed ANT analyst, social things—like class distinctions in taste in the silk and nylon example, but also groups and power—must constantly be constructed or performed anew through complex engagements with complex mediators. There is no stand-alone social repertoire lying in the background to be reflected off, expressed through, or substantiated in, interactions (as in an intermediary conception).[3]

Central to ANT is the concept of translation which is sometimes referred to as sociology of translation, in which innovators attempt to create a forum, a central network in which all the actors agree that the network is worth building and defending. In his widely debated 1986 study of how marine biologists try to restock the St Brieuc Bay in order to produce more scallops,[8]Michel Callon has defined 4 moments of translation: problematisation, interessment, enrollment and mobilisation of allies.

In the above examples, “social order” and “functioning car” come into being through the successful interactions of their respective actor-networks, and actor-network theory refers to these creations as tokens or quasi-objects which are passed between actors within the network.

As the token is increasingly transmitted or passed through the network, it becomes increasingly punctualized and also increasingly reified. When the token is decreasingly transmitted, or when an actor fails to transmit the token (e.g., the oil pump breaks), punctualization and reification are decreased as well.

They locate agency neither in human “subjects” nor in non-human “objects”, but in heterogeneous associations of humans and nonhumans.

ANT has been criticized as amoral. Wiebe Bijker has responded to this criticism by stating that the amorality of ANT is not a necessity. Moral and political positions are possible, but one must first describe the network before taking up such positions. This position has been further explored by Shapiro who contrasts ANT with the history of ecology, and argues that research decisions are moral rather than methodological, but this moral dimension has been sidelined.[10]

Whittle and Spicer note that "ANT has also sought to move beyond deterministic models that trace organizational phenomena back to powerful individuals, social structures, hegemonic discourses or technological effects. Rather, ANT prefers to seek out complex patterns of causality rooted in connections between actors." They argue that ANT's ontological realism makes it, "less well equipped for pursuing a critical account of organizations ­that is, one which recognises the unfolding nature of reality, considers the limits of knowledge and seeks to challenge structures of domination." [11] This implies that ANT does not account for pre-existing structures, such as power, but rather sees these structures as emerging from the actions of actors within the network and their ability to align in pursuit of their interests. Accordingly, ANT can be seen as an attempt to re-introduce Whig history into science and technology studies; like the myth of the heroic inventor, ANT can be seen as an attempt to explain successful innovators by saying only that they were successful. Likewise, for organization studies, Whittle and Spicer assert that ANT is, "ill suited to the task of developing political alternatives to the imaginaries of market managerialism."

Key early citicism came from other members of the STS community, in particular the "Epstemological Chicken" debate between Collins and Yearley with responses from Latour and Callon as well as Woolgar. Collins and Yearley accused ANTs approach of collapsing into and nedless relativist regress. [12] Some critics [attribution needed] have argued that research based on ANT perspectives remains entirely descriptive and fails to provide explanations for social processes. ANT—like comparable social scientific methods—requires judgement calls from the researcher as to which actors are important within a network and which are not. Critics such as[attribution needed] argue that the importance of particular actors cannot be determined in the absence of “out-of-network” criteria. Similarly, others argue that actor-networks risk degenerating into endless chains of association (six degrees of separation—we are all networked to one another). Other research perspectives such as social constructionism, social network theory, Normalization Process Theory, Diffusion of Innovations theory are held to be important alternatives to ANT approaches.

In a workshop called “Actor Network and After”, Bruno Latour stated that there are four things wrong with actor-network theory: “actor”, “network”, “theory” and the hyphen. In a later book however (Reassembling the Social: An Introduction to Actor–Network–Theory), Latour reversed himself, accepting the wide use of the term, “including the hyphen” (Latour 2005:9). He also remarked how he had been helpfully reminded that the ANT acronym “was perfectly fit for a blind, myopic, workaholic, trail-sniffing, and collective traveler” (the ant, Latour 2005:9) — qualitative hallmarks of actor-network epistemology.

↑Michel Callon (1986). “Some Elements of a Sociology of Translation: Domestication of the Scallops and the Fishermen of St Brieuc Bay.” In John Law (ed.), Power, Action and Belief: A New Sociology of Knowledge (London: Routledge & Kegan Paul).

John Law (1987). “Technology and Heterogeneous Engineering: The Case of Portuguese Expansion.” In W.E. Bijker, T.P. Hughes, and T.J. Pinch (eds.), The Social Construction of Technological Systems: New Directions in the Sociology and History of Technology (Cambridge, MA: MIT Press).